October 22, 2010
Text: Roland Wengenmayr
Anyone who discusses high-temperature materials with Martin Jansen quickly sorts our world into an imaginary temperature scale. We live at the very bottom, on a small, cool island where solid matter is possible. Above 4,000 degrees Celsius or so, all the solid materials with which we are familiar melt or decompose. When viewed on a cosmic scale, this is not particularly hot – temperatures of 15 million degrees Celsius, for instance, prevail in the center of our Sun.
Jansen presents a diagram that can be read as a kind of treasure map in the search for high-temperature materials. At the top of the hot hit-list is an alloy of tantalum, zirconium and carbon with a decomposition temperature of just under 4,000 degrees Celsius. Carbon follows in second place, at around 3,800 degrees – but not in air, as the oxygen would have caused it to burn up before then. “The sequence of these materials has been the same for 50 years,” explains the chemist, since science has not found a more heat-resistant material during this time. Obviously, even the strongest chemical bonds can hold atoms together as solid matter only at up to around 4,000 degrees Celsius.